Simple large neighbourhood search strategy: upon restart, for each variable in x ,
the probability of it being fixed to the previous solution is percentage (out of 100).
Start from an initial solution y .

Constrains the elements of x to define a circuit where x [ i ] = j means
that j is the successor of i . Additionally, constrain z to
be the cost of the circuit. Each edge cost is defined by array c . The variables
y [i] are constrained to be the edge cost of the node x [i].